This invention relates to a marine propulsion engine and more particularly to an improved arrangement for locating an electrical generator in a marine outboard drive.
As is well known, one common form of marine propulsion unit is an outboard motor. Outboard motors are extremely compact power sources and include a powerhead that contains an internal combustion engine which drives a propulsion device for propelling the watercraft. Conventionally, a protective cowling is provided around the engine so as to improve the appearance, reduce noise transmission and otherwise provide a neater and more serviceable unit.
It has been the practice to provide a magneto generator driven from the crankshaft of the engine so as to provide not only the power for firing the spark plugs but also auxiliary electrical power for various accessories both for the engine and also for the associated watercraft. Conventionally outboard motors have the engines positioned so that the output shaft rotates about a vertically extending axis and the magneto generator is positioned at the top of the engine. However, with increasing demands on the electrical generating capacity, it has been proposed to employ a separate generator for generating electrical power. This may be required to operate other components of the engine such as solenoids and the like for fuel and/or fuel/air injectors, for driving other engine accessories that require electrical power and for providing electrical power for the associated watercraft.
As is well known, such outboard motors operate in an atmosphere where there is a large amount of water vapor present. It is also necessary to draw atmospheric air into the protective cowling for induction into the engine for its combustion operation. Although the air induction system normally includes devices which are intended to separate, as much as possible, the water from the air inducted, nevertheless there is a high amount of water vapor present in the air that is inducted.
This induction air flows through the interior of the protective cowling and even though shielding is employed for the electrical generator, a large amount of moisture ladened water can come in contact with the generator with conventional constructions. This provides obvious disadvantages.
It is, therefore, a principal object of this invention to provide an improved powerhead construction for an outboard motor wherein the electrical generator will not be subject to large amounts of water ladened air.
It is a further object of this invention to provide an improved component layout and induction system for the powerhead of an outboard motor so as to protect the electrical generating apparatus from the intrusion of large amounts of water.
It is a further object of this invention to provide a layout for the powerhead of an outboard motor wherein the induction air is routed away from the electrical generator.